In conventional commercial aircraft wing design, it is common to use a structural box to carry the majority of the load developed by lift and other high load devices. An example of part of such a box 1 is illustrated in the perspective view of FIG. 1 from which it can be seen that it is built from a number of different sections including spars 2, ribs 3 and stringers 4, which form the main load-bearing structural components of the wing. The box 2 is covered with an outer skin 5. The spars 2 are the principle lateral members of the load-bearing structure and these are connected together with the ribs 3 that provide support and strength to the structure. The stringers 4 are attached to the outer skin 5 to provide longitudinal reinforcement.
Each of the above-mentioned sections are bolted together to form the wing box section. However, this requires significant expense in drilling holes, deburring, sealing and fitting of the nuts and bolts. The nuts and bolts also add significant weight to the structure.
Although the use of at least some bolts can be avoided by forming the box structure from a composite material with the stringers co-cured into the box, or by forming them with a sandwich structure or with wound composite cells, such structures are prone to damage and moisture ingress.
The present invention seeks to overcome or substantially alleviate at least some of the problems with conventional assemblies referred to above.